Thanks!

There are three color versions among this kind of sunflower—one that's all yellow, and two others where the central parts of the petals are either yellowish-orange or reddish-orange. Last year (when we also had volunteers) we didn't have any of the reddish blossoms, so I didn't expect any this year. But we've got some anyway. Either sunflower genetics are more complex than I imagined, or we had some seeds in the ground from a previous year.